The present invention relates to a novel adhesive organopolysiloxane composition or, more particularly, to an organopolysiloxane-based adhesive composition capable of exhibiting excellent adhesive bonding strength on various kinds of substrate materials including metals, plastics, ceramics and the like even without a pretreatment of the substrate surface with a primer composition or even at room temperature so as to be useful in various industrial fields such as electric, electronic and architectural industries.
Among the various types of adhesive compositions used for adhesive bonding of parts in electric and electronic industries or as a sealing material of buildings in architectural works including polyurethane-based, acrylic resin-based, epoxy resin-based and silicone-based ones, the silicone- or organopolysiloxane-based adhesive compositions are widely used as a high-grade adhesive in view of the outstandingly superior performance in respects of their excellent heat resistance, weatherability and electric properties as well as rapid relaxation of the stress produced by heating and cooling.
Silicone-based adhesive compositions are usually formulated with an adhesion-improver for which many proposals and attempts have been made heretofore. For example, Japanese Patent Kokai 48-16952 proposes use of an organopolysiloxane having at least one hydrogen atom directly bonded to the silicon atom and at least one trialkoxysilyl group simultaneously in a molecule as the adhesion-improver. Japanese Patent Kokai 50-39345 proposes use of an organopolysiloxane having at least one hydrogen atom directly bonded to the silicon atom and at least one ester group and/or glycidyl group simultaneously in a molecule as the adhesion-improver. Further, Japanese Patent Publications 52-8854 and 55-41702 disclose a reaction product of an aminoalkyl alkoxy silane and a glycidyloxyalkyl alkoxy silane as the adhesion-improver of a silicone-based adhesive composition.
The silicone-based adhesive compositions in the prior art admixed with the above mentioned adhesion-improvers, however, are not quite satisfactory. In recent years, moreover, various kinds of materials having little susceptibility to adhesive bonding have come to prevailing use in various industrial fields so that these prior art adhesive compositions can no longer comply with the demand for effectively bonding these hardly bondable materials. Another problem in these prior art adhesive compositions consists, while the adhesive composition must be stored in two packages for different ingredients since a ready-mixed adhesive composition has a limited pot life, in the storage stability of some ingredients of the composition resulting in the loss of the adhesive bonding power, in particular, when such an ingredient is compounded after a prolonged storage at room temperature or an elevated temperature. Moreover, some of the silicone-based adhesive compositions cannot exhibit full adhesive bonding strength when the bonding work therewith is undertaken at room temperature so that the application of the adhesive composition to the use as a sealing material of buildings are greatly limited.
Japanese Patent Publications 52-8854 and 55-41702 teach that the adhesive bonding strength by using a hydrosilationcurable silicone-based adhesive composition can be improved by admixing the adhesive with an adhesion improver which is, for example, an organosilicon compound expressed by the structural formula ##STR1## This adhesive composition, however, is not quite satisfactory becaause improvement in the adhesive bonding strength therewith can be obtained only when it is cured at a relatively high temperature.